This invention relates generally to shaft coupling means, and more specifically pertains to a bearing interconnecting torque limiting overload coupling for preventing shaft rotation at forces exceeding the designed torque for the operating machinery.
A variety of styles of shaft coupling devices are available in the prior art, and usually are provided for coupling the drive shaft of a motor or speed reducer with a main driven shaft supporting the work component being turned. Many of these coupling devices are constructed in the category of flexible couplings, and any of a variety of connectors that are designed for providing a transmission of rotatable or torque forces from a drive shaft to the intended driven shaft, or the like. In addition, safety means has on occasion been designed into these type of couplings, functioning in the manner of safety devices to prevent the exertion of excessive torque forces upon the driven shaft from damaging the drive shaft and its prime mover, or even from causing damage to the tool actively performing work upon the machinery and exerting the torque in the first instance. Many of these safety devices have been designed in the category of mechanically activated torque couplers, and as can be seen in the United States patent to Schultz, U.S. Pat. No. 2,771,171, a variety of magnetic pole pieces are arranged within a rotor means and normally effect a revolving of a driven member and its axial shaft for furnishing force transmission for rotation of a pair of axial shafts, but yet in the event that excessive force is applied to one of the shafts then the magnetic means is disengaged for curtailing the rotation of the driven shaft. The shown magnetically operated torque coupler of this United States patent, while it may be effective in its operations, it is quite dissimilar from the mechanically actuated torque limiting means of the current invention.
An additional variety of magnetic coupling devices for preventing overload force from being exerted upon a driven shaft, and which finds significant usage in the textile industry, as when spindles of yarn are being wound, and thereby the tension upon the yarns becomes rather critical and when exceeded can cause a break down in its windings, are shown in the United States patents to Cowell, U.S. Pat. No. 3,221,389, and the United States patent to Gollos, U.S. Pat. No. 3,339,819. This latter patent is pertinent for disclosing a series of spherical projections that contact and intermesh with cups formed upon an opposing annular surface, these two separate components being held together through the agency of permanent magnerts.
Further type of magnetic torque limiting devices, and specifically for use in low force operating mechanisms, such as phonograph record players or sound recorders, are shown in the two United States patents to Tiffany, U.S. Pat. No. 1,136,739, and Cornwell, U.S. Pat. No. 2,300,778.
The combination of magnetic couplers having spring biasing to determine the degree of force necessary for disengaging a coupling has also been available in the prior art, as shown in the United States patent to Allen, U.S. Pat. No. 3,053,365. And, other forms of connectors, which generally have utilized the permanent magnet approach for effecting torque control are shown in the additional United States patent to Woolley, U.S. Pat. No. 3,277,669; the United States patent to Hornschuch, et al. U.S. Pat. No. 3,159,725; the U.S. patent to Spodig, U.S. Pat. No. 2,943,216; the United States patent to Beeston, Jr., U.S. Pat. No. 2,885,873; and finally, the United States patent to Hoad, U.S. Pat. No. 2,746,691, which utilizes a frictional connection between magnets for determining the degree of torque necessary to effect discoupling of its torque limiting device.
Various ball detent couplings are available in the art. Some are shown in the U.S. Pats. No. 3,701,404, No. 3,680,673, No. 3,893,553; No. 3,981,382, No. 3,979,925, No. 3,942,238, No. 3,927,537, No. 3,930,382, and No. 3,866,728.
While all of the foregoing disclosures may be effective for achieving their particular intended results within specific types of mechanical devices and apparatuses, the current invention, a hereinafter to be summarized, and described, embodies rather distinct structure that operates rather differently from any of these prior art, and attains rather precise torque limiting connection between not only a shaft to shaft connection, but also between a combination of shafts, flanges, and dials, depending upon the type of industrial machinery comprising the rotating part, and that which is to be rotated.
It is, therefore, the principal object of this invention to provide a totally mechanical torque limiting overload coupler that may be used intermediate rotating and rotatable parts, of different designs, for achieving precise, but yet adjustable, discoupling of such parts when the force of rotating torque exceeds that for which the machinery was designed.
Another object of this invention is the provision of a torque limiting device which incorporates spring means that may be varied in its quantity of usage so as to provide for major adjustments in the degree of torque that may be withstood by the coupler during its application.
In view of the foregoing, it is yet another object of this invention to provide a retainer in the form of a threaded nut that biases against the aforesaid spring means for furnishing a fine adjustment in the degree of torque being withstood by this coupler before its disengagement.
Yet a further object of this invention is the provision of the usage of a combination of bearing means, preferably in the form of ball bearings, and tapered pins, that function to insure connection of the rotating and rotatable parts of machinery together, but which bearings and pins flexurally disconnect from their seats when the maximum torque force is reached and exceeded.
Yet another object of this invention is the provision of an overload coupling which incorporates rather few functioning components, but yet is totally mechanically operative, and does not rely upon any other extraneous force means, such as a magnetic force, other than its purely mechanical coupling which disengages under the influence of excessively applied torque.
A further object of this invention is the provision of a torque limiting overload coupling which is relatively fascile in its adjustment for attaining precise settings for accommodating applied torque forces during usage of machinery.
A further object is to attain a precise repositioning in register between the rotatable and rotating components of a machine.
Another object is to attain a highly reliable operating coupler that is capable of functioning even in the presence of fretting.
These and other objects will become more apparent to those skilled in the art upon reviewing the summary of this invention, and upon undertaking a study of its preferred embodiment in view of the drawings.